<nav class="navbar navbar-inverse navbar-fixed-top">
  <div class="container">
    <div class="navbar-header">
      <a class="navbar-brand" href="#">返回</a>
    </div>
    <div class="collapse navbar-collapse navbar-ex1-collapse">
      <ul class="nav navbar-nav">
        <button class="btn btn-primary" type="button">
          Messages <span class="badge">{{ unreadMessagesCount }}</span>
        </button>
      </ul>
    </div>
  </div>
</nav>
